GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn the ignition to the ON position.
  2. Place the gear selector lever to the REVERSE position.

Do both backup lamps illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 9

Go to Step 4

4

Do the INTERIOR lamps dim normally?

Go to Step 6

Go to Step 5

5

  1. Disconnect the body control module (BCM) connector C1.
  2. Using a test lamp connected to ground, probe the CHMSL/Back-up fuse voltage supply circuit.

Does the test lamp illuminate?

Go to Step 8

Go to Step 7

6

Test the backup lamps voltage supply circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Test the CHMSL/BACKUP Fuse voltage supply circuit for a poor connection open or an short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the repair?

Go to Step 11

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9

Repair the open or the high resistance in the inoperative backup lamp power supply or the ground circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 11

--

10

Replace the accessory wiring junction block. Refer to Accessory Wiring Junction Block Replacement .

Did you complete the repair?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2